Cardiology Beyond Single Imaging Modality

Cardiovascular (CV) imaging plays a crucial role in declining mortality and optimal disease management. Knowledge of various imaging modality is vital for understanding and management of patients of various CV diseases. Since the first A-mode echocardiogram, there have been great revolutional changes. However, the imaging principal is exactly the same. Echocardiogram and nuclear modality were the only clinically available imaging for management in patients with different CV diseases. The introduction of cardiac magnetic resonance (CMR), computer tomography (CT), three-dimensional (3D) printing, and strain echocardiography makes things quite different. Multi-modality imaging (MMI) plays a role in all CV diseases that includes ventricular function, coronary artery disease, valvular disease, congenital heart disease, intervention guidance, and vascular diseases.

In less than fifteen years, as a non-invasive imaging option, CMR has grown from a being a mere curiosity to becoming a widely used clinical tool for evaluating CV disease. CMR is now routinely used to study myocardial structure, cardiac function, macro vascular blood flow, myocardial perfusion, and myocardial viability. CMR provides a number of key tools to the clinician to evaluate cardiovascular pathologies. Among available imaging modalities to assess global and regional ventricular function, cine CMR based measurements are considered the ‘gold standard.’ While more involved than echocardiogram, CMR based phase contrast methods are robust in the evaluation of regurgitant volume and valvular function.

CT scan have been able to segment the heart better than Echocardiogram. Computers can combine these pictures to create a 3D model of the whole heart. This imaging test can help doctors detect or evaluate coronary heart disease, calcium buildup in the coronary arteries, problems with the aorta, problems with heart function and valves, and pericardial disease. This test may be also used to monitor the results of coronary artery bypass grafting or to follow up on abnormal findings from earlier chest x-rays. Different CT scanners are used for different purposes. A multidetector CT is a very fast type of CT scanner that can produce high-quality pictures of the beating heart and can detect calcium or blockages in the coronary arteries. An electron beam CT scanner can also show calcium in coronary arteries.

3D printing is a fabrication technique used to transform digital objects into physical models. Also known as additive manufacturing, the technique builds structures of arbitrary geometry by depositing material in successive layers based on a specific digital design. Several different methods exist to accomplish this type of fabrication and many have recently been used to create specific cardiac structural pathologies. While the use of 3D printing technology in cardiovascular medicine is still a relatively new development, advancement within this discipline is occurring at such a rapid rate that a contemporary review is warranted.

With rapid advances in imaging technology, current fellows in training and future consultants will frequently be required to use MMI in patient care. CV imaging is fundamentally about the information in the image, not how it is acquired. MMI has been the area of discussions for more than a decade, and the 2015 Core Cardiology Training Symposium guidelines published in May 2015 have further reinforced its importance. Nearly everyone agrees that MMI training is imperative, and most fellows in cardiology programs who are interested in careers in noninvasive imaging have expressed strong interest in acquiring such expertise and eagerly ask about its formal inception. However, despite all of the interest and goodwill, the practical implementation of MMI training has been slow.

Cardiac MMI is a highly dynamic field of continuing research driven by the constant technological advances and innovation of noninvasive imaging and the increasing clinical interest. Its impact extends beyond its clinical utility onto the organization of diagnostic healthcare structures. Furthermore, there is a belief that too much imaging is being done at significant cost and without strong evidence that this amount of imaging is needed or indeed improves outcomes. As part of U.S. healthcare reform efforts, physicians will be required to document that they are following appropriate use criteria (AUC) for outpatient medical imaging orders by using clinical decision support software documentation. The software must be certified by the Centers for Medicare and Medicaid Services in order to receive full reimbursement for diagnostic imaging services for Medicare and Medicaid patients. This will affect advanced outpatient imaging for CT, MRI and nuclear imaging. These new AUC are intended to provide guidance for clinicians when choosing among available testing modalities for various cardiac diseases.

In the assessment of CV disease, multiple imaging modalities may contribute toward determining the diagnosis, prognosis, and approach to treatment. However, each imaging modality may provide relevant information regarding more than one of these clinical needs. Therefore, to explore fully the potential impact of imaging, the strategy should be individualised according to the specific clinical needs and AUC.

Fawaz Alenezi Headshot
Dr. Fawaz Abdulaziz M Alenezi is a Clinical Imaging Fellow at the Duke University Health Systems. He conducts medical research on the derivation and validation of novel echocardiographic approaches to myocardial deformation and a new echocardiographic technique which assists patients with heart ventricular function.


Hypertension In 2017— Individual VS Public Health Goals

Hypertension has obviously been one of the main stays of cardiovascular (CV) medicine for a long time and it is the single most modifiable CV risk factor in the world today. Hypertension had a great deal of evolution since publication of the landmark 1977 Joint National Committee report there has been progressive improvement in awareness, treatment, and control of high blood pressure (BP). Although several BP guidelines have been published since 2003, the 2017 guideline is the most comprehensive that has a new classification, definition and different goals for BP reductions.

The new guideline defines normal BP as below 120/80 mmHg and elevated blood pressure as 120 to 129 mm Hg systolic with a diastolic pressure below 80 mm Hg. Stage 1 hypertension is defined as 130 to 139 mmHg systolic or 80 to 89 mmHg diastolic, and stage 2 hypertension as 140/90 mm Hg or higher (the old definition of hypertension). What is now called stage 1 hypertension was previously labeled “prehypertension” a term meant to alert patients and to prompt physicians to provide lifestyle education to help delay development of hypertension.

Adults with an average systolic BP of 130 to 139mmHg or diastolic BP of 80 to 89mmHg have about a 2-fold increase in CV disease risk compared with a normal BP (SBP < 120 mmHg and DBP < 80 mmHg). Unlike previous guidelines, the 2017 guideline emphasizes individualized CV risk assessment and aggressive management of BP at levels of 140/90 mm Hg or higher in patients with a 10-year risk of CV events of more than 10%. Although the 10% 10-year-risk designation is not based on randomized, controlled trials, patients with BP of 130 to 139/80 to 89 mmHg would still receive non-pharmacologic treatment, unless they had a 10-year risk above 10%; in that case, a single antihypertensive agent is recommended, in concert with lifestyle changes.

Accurate and proper measurement of BP is the first most important and critical step to the diagnosis hypertension. In addition to careful BP measurement, the new guideline highlights the increasingly important role of out-of-office BP readings for confirming hypertension and recognizing white-coat and masked hypertension. It also emphasizes contemporary strategies to improve BP control, including ways to successfully implement and sustain non-pharmacological interventions, improve medication adherence, use a structured team-based approach to care, and take advantage of health information technology.

According to the new BP definitions, prevalence of hypertension increased and there is concern that a new disease designation can become a mandate for pharmacologic treatment without consideration of the patient’s risk level. However, this was an area of discussion and was explained very well in this version of guidelines. Although there are positive aspects of targeting higher-risk people with lower blood pressure for risk-factor modification, an individualized approach to hypertension can help determine the best choice for first-line therapy.

In the public health level there is a morbidity and mortality benefit, but in the individual patient level this may be hard to achieve specifically in asymptomatic patients. We are still not doing well in lowering BP and almost half of the patients are not achieving the individualized goals. However, this is the biggest place where we can have an effect and obviously why there is a national concern! It’s reasonable to consider more aggressive treatment goals in the highest-risk patients, but understanding the guideline and considering each patient according to their risk factors and complex medicine problems become more critical.

Fawaz Alenezi Headshot
Dr. Fawaz Abdulaziz M Alenezi is a Clinical Imaging Fellow at the Duke University Health Systems. He conducts medical research on the derivation and validation of novel echocardiographic approaches to myocardial deformation and a new echocardiographic technique which assists patients with heart ventricular function.


Strain Echocardiography: Values And Limitations – My Experience

“If echocardiographers are to stand still, depend on standard 2D echo imaging using equipment produced a decade ago and not upgraded since, perform ‘‘ejectionfractionograms’’, focus primarily on the left ventricle and simply ‘‘eyeball’’ the other chambers, and avoid new methods such as strain imaging and contrast echo because they are perceived as ‘‘a waste of time’’, then I fear that echocardiography will be passed by. As the dinosaurs illustrated, we need to adapt and continue to evolve, or face the consequences”.
Alan Pearlman- JASE editor, 2010

My research experience focused on heart failure and I conducted medical research on the derivation and validation of novel echocardiographic approaches to myocardial deformation. I have been heavily involved with all projects using strain echocardiography at Duke University (~ 40 projects over the last 5 years). My research has focused on 1) using echocardiographic methods to understand cardiac diseases through in depth pheno-typing, and 2) Left and right atrium strain. I have completed > 10,000 speckle tracking strain measurements analysis on different cardiac diseases and on different cardiac chambers.

Speckle Tracking Strain: Speckle tracking strain imaging has been around for quite a while and we celebrated the first decade 3 years ago, whereas the technique described in 2004 (Leitman M-JASE) and clinical applications appeared around 2005 (Notomi Y- JACC). Since then, the interest has risen dramatically and so far we have > 5000 publications on this topic. Left ventricular (LV) ejection fraction (LVEF), the most widely used measure of cardiac function, has important limitations including low sensitivity for incident HF, technique-related variability and does not directly assess LV contractility. Global longitudinal strain (GLS) is the most studied among strain parameters and its prognostic value has been demonstrated in several clinical scenarios. GLS was widely adapted by cardio-oncology and some studies showed that less negative GLS values at completion of chemotherapy predicted future LV dysfunction, despite normal LVEF. GLS played a vital role in the screening, diagnosis, and management of hypertrophic cardiomyopathy, amyloidosis, valvular heart disease, heart failure and many other diseases where the reduction on LVEF may be a late phenomenon or less sensitive.

Inter-Vendor Variety: GLS inter-Vendor variety has dramatically dropped over a short period of time. However, still if we look at the same images with different software vendors, we may have different values. This difference is due to several factors: 1) Image quality and acquisition; 2) Software used; 3) Where to measure (endocardial, myocardial, median); 4) Post-processing of data; 5) Patients age, gender variabilities and loading conditions. Recent study by (Farsalinos KE- JASE, 2015) showed that the mean values of GLS between different software vendors was almost 3.6%. I still think this is a big difference, however the good news from this study is that the reproducibility of GLS measurement seemed to be very good and better compared to routinely used LVEF. The study also showed that GLS has much less variation than other traditional echo parameters (E/A, wall thickness, LVEDD, EF, and E’).

Regional Strain: With regard to regional (segmental) function, we now have, for the first time, the possibility to measure regional myocardial function. However, I think this is more challenging than GLS, and there is still progress to be made. The challenges become because we have only one segment to work with, and less data to average. Tracking quality becomes more important, regional artifacts matters more, definition of sample position more relevant, and more importantly, we cannot simply measure peak values anymore. For regional analysis, the strain curve shape (not peak values, because peak values can be the same), become critical. Regional strain measurements have much higher variability among vendors when compared with GLS. Furthermore, I have notice a big difference when I measuring the normal segment and the abnormal (scar) segment.

Strain Patterns: Specific strain patterns, such as that attributed to cardiac amyloid, I believe the severity of the disease matter more than the etiology. I think some of chronic global heart diseases states such as hypertension, aortic stenosis, heart failure with preserved EF, etc. share similar strain patterns and the pattern depends not on the etiology, but on the severity of disease states. For example, in more severe (late stage) aortic stenosis, or hypertension, I have notice similar strain patterns that has been described in cardiac amyloid, that affect mainly the basal/med segments and spares the apex. The LV apex is comprised mainly of circumferential muscle fibers, that are facing different hemodynamics load (BP) or may be histologically different from the longitudinal muscle fibers (basal/ med). On the other hand, do these chronic diseases also have accumulation of proteins similar to amyloid and not necessarily represent a complete picture of cardiac amyloid. Still an area of research!

Normal Values: What is the reference values? is another common question. Personally, I think no normal values could be given and each echo-lab should build up their normative values according to the local data, software vendor used, image acquisition, experience and the echo machine setup. Much remains to be done on improving the software, acquisition layered strain, and updating the myocardial function documents. For this discussion, I focused on the 2D LV GLS, though there is also promising research on the left atrium and right heart, and right atrium strain which have traditionally been hard to characterize.

In summary, I think GLS is ready for clinical practice. Its robust, reproducible and has been shown to add unique data that can guide diagnosis and management. I recommend GLS as a valuable complement to traditional function parameters. Further studies are needed to standardize vendors, recognizing specific strain patterns and to determine if there are age, gender variabilities or loading conditions difference.

Fawaz Alenezi Headshot
Dr. Fawaz Abdulaziz M Alenezi is a post-doctorate associate at the Duke University Health Systems. He conducts medical research on the derivation and validation of novel echocardiographic approaches to myocardial deformation and a new echocardiographic technique which assists patients with heart ventricular function.



Tips For Early Career Physicians, AHA 2017- Anaheim, CA

As an attendee of the 2017 American Heart Association (AHA) Scientific Sessions in Anaheim- California, I have had a chance to attend one of the most comprehensive scientific sessions on tips for early career physicians. This session was very rich and answered some of the questions that we face as early career cardiologists. Particularly, questions on the optimal path of training for trans-catheter valves, and things we don’t learn in residency. Although clinical practice guidelines remain the primary mechanism for offering evidence-based recommendations, these sessions are intended to provide guidance for clinicians in areas where evidence may be limited. I found the topic of this session to be quite interesting, and I hope all derive as much as I did from these tip sessions that the AHA provides.

Trans-catheter aortic valve replacement (TAVR) and trans-catheter mitral valve replacement (MVR) utilize new and transformational technology for severe aortic stenosis (AS) and significant mitral valve regurgitation respectively, in patients for whom surgery is not an option. As we all know, TAVR and MVR have been increasing in volume over the past several years, but this has not really been matched by corresponding data describing the learning curve for this new technology. This session builds on the recommendations in the 2014 AHA/ACC guideline for the management of patients with valvular heart disease and highlighted the optimal path of training as an important step for the best outcome.

Despite the great success of TAVR, close to 25% of TAVR patients die within 1 year of their procedure, and others survive the intervention but remain with poor overall health status. Training programs are one of the important factors that need to be addressed carefully. To summarize, in my opinion, I think there needs to be further development of this subject, particularly in terms of training and developing new trans catheter centers. Currently there’s no real data-driven guidelines in terms of how people become proficient in this technology, nor is there guidance for training methodologies pertaining to TAVR or trans-catheter MVR. Here are some important points that we need to ask ourselves prior to the start any training:

  • Do self-assessment (what are your interests, strength and weakness).
  • Have you been taught a problem solving approach?
  • Do you need to do 10 cases to feel comfortable with a procedure? 100?
  • Ask for candid assessment from your trainers.
  • Be careful about taking chances in the first year!
  • Can introduce new technologies to practice.

In this context, this session highlighted the importance of developing strategies and partnerships that allow initiation of new TAVR and MVR programs that can produce efficacious and safe results that are comparable to existing national benchmarks. It is my hope that other attendees will take full advantage of all the session offerings such as this one.  This conference is, without a doubt by far, the most educational and enriching experience!

Fawaz Alenezi Headshot

Dr. Fawaz Abdulaziz M Alenezi is a post-doctorate associate at the Duke University Health Systems. He conducts medical research on the derivation and validation of novel echocardiographic approaches to myocardial deformation and a new echocardiographic technique which assists patients with heart ventricular function.